# Calculations

## Mass Converter

Here, the masses in different scales can be converted.

Just enter the value, unit and confirm using 'OK '.

Metric: | 1 | kg | kilogram |

1000 | g | gram | |

0.001 | t | ton | |

0.01 | dz | Doppelzentner | |

50000 | Kt. | karat | |

Anglo-American: | 564.383 | dr. | dram |

35.274 | oz. | ounce | |

2.205 | lb. | pound | |

32.151 | oz.tr. | troy ounce | |

Atomic: | 602.214⋅10^{24} | u | cubic yard |

560.852⋅10^{33} | eV | unified atomic mass unit |

## Mass:

**Metric system:** In SI units, the basic unit is the kilogram (kg), what was originally defines as the mass of one litre of water. Nowadays the kilogram is the only SI unit which is not yet defined by natural constants, but by a reference mass, called "International Prototype Kilogram" (IPK), that is preserved in Paris. Because a SI prefix is already part of the name of the base unit (kg), it cannot be combines with other prefixes. To specify different orders of masses, we start at the gram (g = 0.001 kg) and prepone the adequate prefix.

For bigger masses, the unit ton (1 t = 1000 kg) is often used. An older unit is the Doppelzentner (1 dz = 100 kg), which is similar to the English hundredweight.

A further unit, that is used in gemstone industry, is the metric carat (1 Kt = 0.0002 kg).

**Anglo-American system:** In Anglophone countries the following units of mass are used:

The dram (dr.), the ounce (oz.) and the pound (lb.)

It is: 1 lb. = 16 oz. = 256 dr. = 0.453592370 kg.

**Atomic:** The mass of atoms and molecules is given in unified atomic mass units (u). 1 u is defined as 1/12 of the mass of a carbon atom ^{12}C. It is: 1 u = 1.66053878283⋅10^{-27}kg.

In particle physics the mass of the particles is expressed by the rest energy: According to the special relativity theory the rest energy is proportional to the mass:

E = m ⋅ c^{2}

As the speed of light is constant, we can calculate the energy equivalent to the mass.